Plaster mixing device



March 3, 1964 R. C. BLAIR PLASTER MIXING DEVICE Filed Dec. 11, 1961 www fs drm United States Patent 3,123,341 PLASTER MIXING DEVICE Robert C. Blair, Winnipeg, Manitoba, Canada, assignor to Western Gypsum Products Limited, Winnipeg, Manitoba, Canada Filed Dec. 11, 1961, Ser. No. 158,293 3 Claims. (Cl. 259-8) My invention relates to new and useful improvements in plaster mixing devices, particularly centrifugal mixing devices adapted to mix plaster and water into a slurry which is then discharged through a plurality of apertures and is used primarily in the formation of plaster board and the like.

My invention provides a shallow mixing chamber having a rotating disc at the base thereof and a plurality of symmetrically spaced scraper arms spaced above the said disc and rotating therewith adapted to scrape the top of the said mixing chamber; the said mixing chamber being provided with adjustable outlets in the bottom thereof near the periphery.

A further object of my invention is to provide a device of the character herewithin described in which the discharge of the slurry can be controlled, within limits, through each of the apertures thus balancing the quantity discharged by each aperture.

To accomplish this second object of my invention, I provide an adjustable deilector positioned adjacent each discharge aperture adapted to deflect a greater or lesser amount of slurry material into each discharge aperture.

Another object of my invention is to provide a device of the character herewithin described in which clogging or packing is minimized considerably.

Yet another object of my invention is to provide a device of the character herewithin described which is extremely simple in construction, economical in manufacture, and otherwise well suited to the purpose for which it is designed.

With the foregoing objects in view, and such other objects and advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, my invention consists essentially in the arrangement and construction of parts all as hereinafter more particularly described, reference being had to the accompanying drawings in which:

FIGURE 1 is a top plan view of my device.

FIGURE 2 is a section substantially along the line 2 2 of FIGURE 1.

ln the drawings like characters of reference indicate corresponding parts in the different gures.

Proceeding therefore to describe my invention in detail, reference should be made to the accompanying drawings in which reference character generally indicates the mixing chamber comprising a circular base plate 11, a surrounding cylindrical wall 12 and a cover plate 13.

The cover plate 13 is a circular disc, the edges of which engage the upper edge 14 of the surrounding wall 12, said cover disc being held in position by means of a plurality of clamps 15 secured around the periphery of the mixing chamber.

Each of these clamps includes an arm 16 pivotally connected to a lug 17 upon the underside of the base plate 11 by means of pivot pin 18.

An inturned upper end 19 carries clamp bolt 20 extending therethrough and engaging a clamp ring 21 as clearly shown in FIGURE 2.

A circular mixing disc 22 is apertured centrally as at 23 and engages around a shouldered portion 24 of the lower end of a centrally located drive spindle 25. This drive spindle is journalled at the lower end thereof within a thrust bearing 26 secured centrally Within the base plate 11 and extends upwardly through the cover plate ice 13, through a vertical adjusting collar 27 and is supported adjacent the upper end thereof by means of a bearing assembly 28 held by supporting structure 29. The extending end 30 of the shaft is connected to a convenient source of power (not illustrated) so that rotation of the spindle also rotates the mixing disc 22 within the mixing chamber.

The diameter of the disc 22 is slightly smaller than the diameter of the mixing chamber and this disc is provided with a plurality of Scrapers 31 upon the underside thereof and rotatable therewith. These Scrapers scrape the base plate 11 and prevent the build up of plaster thereupon.

A water manifold 32 is secured to the cover plate by means of bolts 33 and is in the form of an elongated cyl- -inder apertured at the base thereof, said apertures communicating with further apertures 34 formed within the cover plate and lying radially thereon. A source of water (not illustrated) is conveyed to the manifold 32 by means of intake 35.

A plaster intake aperture 36 is also formed through the cover plate, spaced from the water intake manifold 32 and a source of gypsum plaster is communicated to this aperture from a convenient supply (not illustrated).

Situated adjacent the periphery of the base plate 11 and substantially diametrically opposite to the water manifold 32, is a plurality of mixed plaster discharge apertures 36 to which downwardly depending discharge spouts 37 are seculed.

A plurality of symmetrically disposed scraper arms 38 are secured to a scraper arm hub 39 mounted around the spindle 25 and upon the mixer plate 22.

Each of these scraper arms 38 extends radially adjacent the periphery of the mixing disc 22 and carries a scraper blade 39 upon the outer end thereof. Reference to FIGURE 2 will show that these scraper arms are situated within the mixing chamber but spaced and parallel from the mixing plate 22. Furthermore, the scraper blades 39 depend downwardly from the ends of the scraper arms and engage the periphery of the mixer disc to which they may be secured by means of bolts 40.

In operation, water and plaster are fed through the relevant intakes and are thrown by centrifugal force onto the outside wall 12 of the mixing chamber in nely divided state, being mixed thoroughly during this action by being forced together in intimate contact while in a tinely divided state, thus forming a slurry which is carried around by the tangential force of the material striking the wall 12, to the discharge apertures and is discharged therethrough. However, it is necessary to control the Volume of slurry being discharged by the various apertures and consequently I have provided means 41 to accomplish this control.

Adjacent each discharge 36 and situated in advance thereof (with respect to the direction of rotation indicated by arrow 42) is a vertically situated deflector bolt or spindle 43 journalled for rotation at the upper end thereof within the periphery of the cover 13 and by the lower end thereof within the base plate 11.

The portion 44 of the bolt or spindle within the mixing chamber is cut away vertically thus forming a at face 45 which acts as a deflecting surface to the slurry being carried around as described so that by adjusting the angle of this planar surface, the discharge of the slurry through the apertures 36 is controlled volumetrcally thus achieving an equal flow from each discharge 36.

Since various modifications can be made in my invention as hereinabove described, and many apparently widely diterent embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained .circular hase plate, a surrounding wall secured thereto,

and a detachable, apertured `cover plate spanning the upper edge .of said wall, said base plate, said surrounding wall, and said cover plate dening a mixing chamber, a :spindle journalled for rotation centrally in said base plate :and extending upwardly therefrom and passing through :said cover plate, said spindle being connected to an associated source of power, a centrifugal mixing disc secured to said spindle below said cover plate, said disc spanning the majority of said base plate, water and plaster intakes formed through said cover plate inboard of the periphery thereof, said intakes being connected to a source of water and plaster respectively, a plurality of vertically situated discharge apertures in said base plate adjacent the periphery thereof, and adjustable means extending through said cover plate and into said mixing chamber adjacent the said surrounding wall and adjacent said discharge apertures, adapted to control the discharge of said mixed plaster through said discharge apertures, said means comprising a vertically situated iloW adjusting spindle bearably supported by the upper end thereof in said cover plate and by the lower end thereof in said base plate, the portion of said flow adjusting spindle within said mixing chamber being cut away along the length thereof thereby presenting a planar surface to the interior of said mixing chamber, said planar surface acting as a material deliector to said discharge aperture.

2. The device according to claim 1 which includes a plurality of scraper arms disposed within said chamber adapted to scrape the inside surface of said apertured cover plate, said scraper arms being secured to the upper surface of said mixing disc and disposed parallel thereto.

3. The device according to claim 2 which includes scraper blades on the outer ends of said scraper arms extending downwardly to said mixer plate periphery and being secured thereto.

References Cited in the le of this patent UNITED STATES PATENTS 2,097,088 Mills Oct. 26, 1937 

1. A DEVICE FOR MIXING PLASTER AND WATER COMPRISING IN COMBINATION A CYLINDRICAL BASE COMPONENT INCLUDING A CIRCULAR BASE PLATE, A SURROUDING WALL SECURED THERETO, AND A DETACHABLE, APERTURED COVER PLATE SPANNING THE UPPER EDGE OF SAID WALL, SAID BASE PLATE, SAID SURROUNDING WALL, AND SAID COVER PLATE DEFINING A MIXING CHAMBER, A SPINDLE JOURNALLED FOR ROTATION CENTRALLY IN SAID BASE PLATE AND EXTENDING UPWARDLY THEREFROM AND PASSING THROUGH SAID COVER PLATE, SAID SPINDLE BEING CONNECTED TO AN ASSOCIATED SOURCE OF POWER, A CENTRIFUGALMIXING DISC SECURED TO SAID SPINDLE BELOW SAID COVER PLATE, SAID DISC SPANNING THE MAJORITY OF SAID BASE PLATE, WATER AND PLASTER INTAKES FORMED THROUGH SAID COVER PLATE INBOARD OF THE PERIPHERY THEREOF, SAID INTAKES BEING CONNECTED TO A SOURCE OF WATER AND PLASTER RESPECTIVELY, A PLURALITY OF VERTICALLY SITUATED DISCHARGE APERTURES IN SAID BASE PLATE 